Why does one of these font-face render in IE8, but the others don't?

Question

Why does this fontface render in IE8:

@font-face {
  font-family: \'Aller\';
  src: url(\'aller_rg-webfont.eot\');
  src: url(\'aller_rg-webfont.eot?#iefix\'         


        

Answer 1

Under IIS (MVC environment) I had to add the following rule to my Web.config: